views:

729

answers:

2

Hello,

I've come across a scenario where I want to pass a large amount of data to a Stored Procedure for generating some dynamic SQL.

The data I want to pass is stored in this Json/C# class object that I use in my ASP.NET MVC web project.

[
 {
  "code":"ABC123",
  "Count": "12998",
  "Params":
  [
    {"name": "Recent", "value": "0-12m"},
    {"name": "Orders", "value": "1"}
  ]
 },
 {
  "code":"ABC124",
  "Count": "13998",
  "Params":
  [
   {"name": "Recent", "value": "0-12m"},
   {"name": "Orders", "value": "2"}
  ]
 },
 {
  "code":"ABC125",
  "Count": "7998",
  "Params":
  [
   {"name": "Recent", "value": "0-12m"},
   {"name": "Orders", "value": "3"}
  ]
 }
]
.....

Then use this text parameter to convert back to a JSON object, I use this in an action filter to convert it to an object.

public class ObjectFilter : ActionFilterAttribute
{

    public string Param { get; set; }

    public Type RootType { get; set; }

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {

        if ((filterContext.HttpContext.Request.ContentType ?? string.Empty).Contains("application/json"))
        {

            object o =

            new DataContractJsonSerializer(RootType).ReadObject(filterContext.HttpContext.Request.InputStream);
            filterContext.HttpContext.Request.InputStream.Seek(0, SeekOrigin.Begin); // Rewind InputStream for other filters

            filterContext.ActionParameters[Param] = o;

        }

        else
        {

            var xmlRoot = XElement.Load(new StreamReader(filterContext.HttpContext.Request.InputStream,

            filterContext.HttpContext.Request.ContentEncoding));

            object o = new XmlSerializer(RootType).Deserialize(xmlRoot.CreateReader());

            filterContext.ActionParameters[Param] = o;

        }

    }

}

and then use C# etc in my CLR Stored Procedure to create a SQL statement such as:

UPDATE [Sample]
SET [Field] =
CASE
WHEN [Recent] = "0-12m" AND [Orders] = "1" THEN "ABC123"
WHEN [Recent] = "0-12m" AND [Orders] = "2" THEN "ABC124"
WHEN [Recent] = "0-12m" AND [Orders] = "3" THEN "ABC125"
...

Is this possible and has anyone ever done anything like this. I've seen a few posts on using a XML parameter but none using a varchar parameter using de-serialized (?) json.

A: 

It is possible; please see the canonical reference on dynamic SQL: The Curse and Blessings of Dynamic SQL

Mitch Wheat
A: 

I've tried to use my code to parse a JSON string parameter but the required namespaces are not available in a SQL CLR project and I have therefore switched to the documented Xml parameter.

Phil